Techniques for sensing the volume and/or viscosity of concrete in a rotating container

ABSTRACT

A system for sensing the volume and/or viscosity of a slurry (e.g., like concrete) contained in a rotating container or drum, having a sensor and a signal processor. The sensor is configured to attach inside a rotating container or drum having a known geometry, sense angular positions of the sensor and also sense associated entry and exit points when the sensor enters and exits the slurry, including concrete, contained in the rotating container or drum, and provide signaling containing information about the angular positions and the associated entry and exit points. The signal processor receives the signaling, and determines corresponding signaling containing information about a volumetric amount, or a viscosity, or both, of the slurry in the rotating container or drum, based upon the signaling received.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit to provisional patent application Ser.No. 62/548,683 (712-2.451//CCS-0143), filed 22 Aug. 2017, as well asprovisional patent application Ser. No. 62/548,699(712-2.452//CCS-0178), filed 22 Aug. 2017; which are both herebyincorporated by reference in their entirety.

This application is related to patent application Ser. No. 14/350,711(712-2.365-1-1), filed 9 Apr. 2014, which corresponds toPCT/US2012/060822, filed 18 Oct. 2012, claiming benefit to provisionalpatent application Ser. Nos. 61/548,549 and 61/548,563, both filed 18Oct. 2011; which are all incorporated by reference in their entirety.

The aforementioned applications were all assigned to the assignee of thepresent application, which builds on this family of technology.

BACKGROUND OF THE INVENTION 1. Field of Invention

This invention relates to a technique for sensing the volume and/orviscosity of concrete in a rotating container or drum.

2. Description of Related Art

The assignee of the present invention has developed a means of measuringentrained air in wet concrete, which is disclosed in the aforementionedpatent application Ser. No. 14/350,711 (712-2.365-1-1). The measurementdevice or acoustic probe is called, or known in the industry as,AIRtrac™ or AIRtrac Mobile™. The AIRtrac™ sensor may be permanentlyinstalled on a rotating container/concrete mixer drum or on the hatchdoor of a concrete mixer drum.

Consistent with that disclosed in the aforementioned patent applicationSer. No. 14/350,711 (712-2.365-1-1), and by way of example, FIGS. 1a to1e show the AIRtrac™ sensor, that is generally indicated as 100 and mayinclude an acoustic-based air probe like element 101. The acoustic-basedair probe 101 may include an acoustic source generally indicated as 102(see FIG. 1d ) configured to provide an acoustic signal into a mixtureof concrete; and an acoustic receiver generally indicated as 104 (seeFIG. 1e ) configured to be substantially co-planar with the acousticsource 102, to respond to the acoustic signal, and to provide signalingcontaining information about the acoustic signal injected into themixture of concrete. By way of example, the acoustic source 102 mayconsist of an arrangement of parts and components and is best shown indetail in FIG. 1d . By way of example, the acoustic receiver 104 mayconsist of at least an arrangement of one or more transducers and fillsand is best shown in FIG. 1 e.

The acoustic-based air probe 101 may include a planar probing surface106 having a first aperture 106 a formed therein configured to receivepart of the acoustic source 102, including a hardened steel piston 122,as best shown in FIG. 1d . At the interface with the planar probingsurface 106, the hardened steel piston 122 is surrounded by acircumferential channel 122 a, so as not to be in physical contact withthe planar probing surface 106. The planar probing surface 106 mayinclude at least one second aperture 106 b, 106 c formed thereinconfigured to receive at least one part 104′, 104″ of the acousticreceiver 104. The part 104′, 104″ are shown as a protective polyurethanerubber member in FIG. 1e . The planar probing surface 106 may beconfigured as a hardened steel face plate, although the scope of theinvention is intended to include using other type or kinds of materialseither now known or later developed in the future. The acousticreceivers 104 are configured in relation to the center of the hardenedsteel piston 122 of the acoustic source 102 and defined by a radius R,as best shown in FIG. 1c , so that the acoustic receivers 104 arearranged and configured substantially on the circumference of a circledefined by the radius R from the center of the hardened steel piston122.

The acoustic receiver 104 may include, or take the form of, a dynamicpressure transducer, as best shown in FIG. 1 e.

In operation, and by way of example, the acoustic receiver 104 may beconfigured to receive acoustic signals, e.g., having a frequency in arange of about 100-500 Hz, including 330 Hz, although the scope of theinvention is intended to include using other frequencies and otherranges either now known or later developed in the future.

By way of example, the acoustic source 102 may include, or take the formof, or be configured as, a floating mass, consistent with that shown inFIG. 1 d.

In FIG. 1d , the acoustic source 102 is shown in the form of a pistonmodule assembly 120 having the rigid hardened steel piston 122configured with a channel 124 to receive, or be coupled to, a pistonshaft 126. The acoustic-based air probe 101 has a base plate disk 125that contains the piston module assembly 120, as well as othercomponents in FIG. 1d . The rigid hardened steel piston 122 is enclosed,surrounded and configured to move in relation to a low durometer castsilicone rubber 123 and photo-etched flexures 127, so as to provide thefloating mass aspect of the acoustic source 102. The low durometer castsilicone rubber 123 may also be configured to perform sealingfunctionality in relation to the mixture of the concrete. The acousticsource 102 may also include a vibration isolated actuator block assembly128, best identified in FIG. 1b , having a stationary voice coilactuator field assembly 130 in combination with a voice coil actuatorfield assembly 132 having an accelerometer transducer configuration. Thevibration isolated actuator block assembly 128 may be configured todrive and vibrate the piston shaft 126, consistent with that shown inFIG. 1d , so as to provide the acoustic signal to the mixture of theconcrete when the acoustic-based air probe is inserted into the mixture.The apparatus 100 may also be configured with signal processingtechnology (not shown) for driving the acoustic source 102, as would beappreciated by a person skilled in the art.

The acoustic-based air probe 101 may include a fluid/media temperaturesensor 134, consistent with that shown in FIG. 1d , configured toprovide a temperature reading of the mixture.

The acoustic-based air probe 101 may include a voice coil temperaturesensor 136, consistent with that shown in FIG. 1d , configured toprovide a temperature reading of the stationary voice coil actuatorfield assembly 130.

The acoustic-based air probe 101 may include two acoustic receivers 104,104′, that may take the form of the two dynamic pressure transducers,consistent with that shown in FIG. 1 e.

The acoustic-based air probe 101 may include some combination of aconnector/wiring cover plate 140, and various connectors configured inrelation to the same, including a pressure sensor no. 1 connector 142for providing the signaling in relation to one pressure sensor, apressure sensor no. 2 connector 144 for providing the signaling inrelation to the other pressure sensor, a voice coil drive connector 146for providing the signaling in relation to the voice coil drive 130(FIG. 1d ), a temperature sensor connector 148 for providing thesignaling in relation to a temperature, and an accelerometer connector150 for providing the signaling in relation to the voice coil actuatormoving coil assembly 132 (FIG. 1d ), all shown in FIG. 1 b.

SUMMARY OF THE INVENTION

The present invention provides a new use of air measurement informationprovided by the AIRtrac™ sensor, e.g., including quality of signal andother diagnostics to discern when the probe is submerged in concrete andwhen it's not. That air measurement information coupled with sensorlocation information provided by the AIRtrac™ sensor, estimated slump,drum speed, drum size and dimensions can all be used to give an accurateestimate of how much concrete is currently in the container/mixer drum.This will particularly useful when part of a load is discharged and aspecific amount of concrete (what should be left in the drum) isrequired for another job.

By way of example, the AIRtrac™ sensor may be mounted on hatch door orside wall of mixer drum. Its power source can be inductive, solar orbattery.

In operation, the AIRtrac™ sensor will report air content in the wetconcrete. Once the concrete is covering the AIRtrac™ sensor, theAIRtrac™ will also begin to report real-time air by volume information.

Particular Embodiments

In its broadest sense, the present invention provides a new and uniquesystem for sensing the volume and/or viscosity of a slurry (e.g., likeconcrete) contained in a rotating container or drum, having a sensor anda signal processor.

The sensor may be configured to attach inside a rotating container ordrum having a known geometry, sense angular positions of the sensor andalso sense associated entry and exit points when the sensor enters andexits the slurry, including concrete, contained in the rotatingcontainer or drum, and provide signaling containing information aboutthe angular positions and the associated entry and exit points.

The signal processor may be configured to receive the signaling, anddetermine corresponding signaling containing information about avolumetric amount, or a viscosity, or both, of the slurry in therotating container or drum, based upon the signaling received.

The system may also include one or more of the following features:

The sensor may include a 3-axis accelerometer configured to respond tothe angular positions of the sensor at given times, and provide angularposition signaling containing information about the angular positions ofthe sensor at the given times.

The signal processor may be configured to determine the volumetricamount based upon static pressure readings contained in the signalingreceived that increase when the sensor enters the concrete and decreasewhen the sensor exits the concrete.

The sensor may include a pressure transducer configured to sense staticpressure when the sensor enters and exits concrete contained in therotating container or drum and provide static pressure signalingcontaining information about the static pressure sensed.

The signal processor may be configured to determine the associated entryand exits points of the sensor using a least squares curve fittingalgorithm.

The signal processor may be configured to determine the volumetricamount based upon acoustic energy readings contained in the signalingreceived that increases when the sensor enters the concrete anddecreases when the sensor exits the concrete.

The sensor may include a piston arranged in the rotating container ordrum and configured to generate pulses; and a pressure transducerarranged in the rotating container or drum at a known distance from thepiston and configured to sense the pulses generated and provide acousticenergy signaling containing information about the pulses sensed,including where the magnitude of acoustic energy sensed by the pressuretransducer is low when the pulses are generated and sensed in air, andwhere the magnitude of acoustic energy sensed by the pressure transduceris high when the pulses are generated and sensed in the concrete.

The signal processor may be configured to determine the viscosity basedupon the amount of “tilt” of the concrete in the rotating container ordrum and the speed of rotation of the rotating container or drum.

The signal processor may be configured to determine the amount of “tilt”of the concrete in the rotating container or drum based upon the angularpositions and the associated entry and exit points when the sensorenters and exits concrete contained in the rotating container or drum.

The signal processor may be configured to determine the rotation speedof the rotating container or drum based upon the angular positions ofthe sensor contained in the signaling received.

The signaling may contain information about constituents of theconcrete, including the amount of water, sand, rock and respectivedensities, and the signal processor may be configured to determine theslump of the concrete, based upon the signaling received.

The sensor may be mounted on a hatch door of the rotating container ordrum, as well as other parts of the rotating container or drum.

The sensor is an acoustic-based sensor.

The Signal Processing Functionality

The signal processor may be configured to receive signaling containinginformation about angular positions of a sensor attach inside a rotatingcontainer or drum having a known geometry, as well as associated entryand exit points when the sensor enters and exits a slurry (e.g., likeconcrete) contained in the rotating container or drum, and determinecorresponding signaling containing information about a volumetricamount, or a viscosity, or both, of the slurry in the rotating containeror drum, based upon the signaling received.

BRIEF DESCRIPTION OF THE DRAWING

The drawing includes FIGS. 1a -6, which are not necessarily drawn toscale, as follows:

FIG. 1a is a perspective view of an acoustic probe that may be used insome embodiments of the present invention.

FIG. 1b is an axial view of one end the acoustic probe shown in FIG. 1a.

FIG. 1c is an axial view of another end the acoustic probe shown in FIG.1 a.

FIG. 1d is a sectional view of the end the acoustic probe shown in FIG.1c along section lines A-A.

FIG. 1e is a sectional view of the end the acoustic probe shown in FIG.1c along section lines B-B.

FIG. 2 is a photograph of a ready mix truck with arrow pointing to hatchdoor indicating potential location of AIRtrac™ sensor installation,which is provided as an example of an AIRtrac™ system installed on ahatch door, and where the hatch door may be located on mixer drum.

FIG. 3 is a photograph of a hatch door with AIRtrac™ sensor installed.

FIG. 4 is a diagram showing an end cross-section of a concrete truckdrum having an AIRtrac™ sensor entering and exiting the concrete as theconcrete truck drum.

FIG. 5 includes FIGS. 5A and 5B, where FIG. 5A is a diagram showing anend cross-section of a concrete truck drum with concrete having a lowviscosity; and where FIG. 5B is a diagram showing the end cross-sectionof the concrete truck drum with concrete having a high viscosity.

FIG. 6 is a block diagram of a system having a sensor and a signalprocessor or signal processing module for implementing the presentinvention.

DETAILED DESCRIPTION OF BEST MODE OF THE INVENTION Summary of BasicInvention

The AIRtrac™ mobile sensor measures air content by actively creatingacoustic waves and measuring the speed of the waves in the concretemedia. This is accomplished by using a piston to “pulse” the concreteand measuring the amount of time it takes for the pulse to travelthrough the concrete and be detected by a pressure transducer that isknown distance away from the piston, e.g., consistent with that setforth above. This works very well for the determination of the aircontent of the concrete mixture but these components can also be used tomeasure other aspects of the concrete. The present invention disclosestwo additional measurements that can be made.

Volume of Concrete

One parameter that is often not known is the precise volumetric amountof concrete that is in a concrete truck, particularly after a partialpour has occurred. Some measurement techniques known in the art look atthe hydraulic loading of the drum, however this is often inaccurate asit requires knowledge of the exact density of the concrete as well asthe knowledge of other parameters such as the air content. Using theAIRtrac™ system a much more direct measurement can be made. Thismeasurement technique utilizes the fact that the AIRtrac™ sensor issubmerged under the concrete for part of the drums rotation and then isout of the concrete for the remainder. In addition, the AIRtrac™ devicehas a 3-axis accelerometer that is used to determine the angularposition of the sensor at any given time. The combination of knowing theconcrete entry and exit angles along with the geometry of the drum, thevolume of the concrete can be calculated. FIG. 4 shows a diagram of howthis can be achieved.

FIG. 4 shows an approximately half full drum. The AIRtrac™ sensor willenter the concrete at about +90 degrees from vertical and exit at about−90 degrees.

This will give an indication that the concrete is occupying about ½ thedrum and the volume can be calculated. A simple calculation can be madefor other concrete entry/exit angles to yield volume.

The angle of the sensor is always available so the remaining aspect ofthe measurement is determination of the concrete entry and exit points.Two ways this can be accomplished utilize the pressure transducer.First, a static pressure can indicate when the sensor is under concrete.While in air above the concrete the pressure transducer will show closeto 0 pressure, but as the senor enters the concrete the weight of theconcrete will cause a pressure reading. This reading will increase untilthe sensor is at the bottom of the drum and then decrease until thesensor emerges from the concrete on the other side. Various analysistechniques including least squares curve fitting can be used toextrapolate the exact entry and exit points of the pressure sensor. Asecond detection technique can utilize the magnitude of the acousticsignal the pressure sensor sees as it is generated by the piston. Air ishighly attenuative to acoustic waves so when the AIRtrac™ is in air thepressure transducer will see very little of the acoustic energygenerated by the piston, while once the sensor is in the concrete thesignal level will rise dramatically. This can also be used to determinewhen the AIRtrac™ sensor enters and leaves the concrete within the drum.

Viscosity of Concrete

A second parameter of the concrete that the AIRtrac™ can determine isthe viscosity of the concrete. The viscosity of a fluid is directlyrelated to the ability of the fluid to flow. Therefore, in a rotatingcontainer or drum like a concrete truck a low viscosity fluid willremain very level while a very viscous fluid will tend to not flow verywell and will ride up the wall of the drum as the drum exits the fluid.FIG. 5 shows diagrams of the effect.

The amount of the “tilt” of the concrete in the drum will depend on theviscosity of the fluid (or concrete) and the speed of rotation of thedrum. The drum rotation speed can be determined by the 3-axisaccelerometer and the “tilt” can be determined by the same techniquesdescribed above. With knowledge of these parameters along with geometricshape of the drum the concrete viscosity can be determined. Furthermore,with knowledge of the concrete constituents including amount of water,sand, rock and their respective densities, the slump of the concrete canbe determined.

The System 10

FIG. 6 shows a system 10 having a sensor (e.g., such as anacoustic-based sensor like element 100) and a signal processor or signalprocessing module 12 for implementing the present invention.

In operation, the sensor 100 may be configured to attach inside arotating container or drum like that shown in FIGS. 2-3 having a knowngeometry, sense angular positions of the sensor as the drum rotates, andalso sense associated entry and exit points when the sensor enters andexits a slurry (e.g., like concrete) contained in the rotating containeror drum, and provide signaling containing information about the angularpositions and the associated entry and exit points.

The signal processor 12 may be configured to receive the signalingsensed, and determine corresponding signaling containing informationabout a volumetric amount, or a viscosity, or both, of the slurry (likeconcrete) concrete in the rotating container or drum, based upon thesignaling received.

The functionality of the signal processor or processor control module 12may be implemented using hardware, software, firmware, or a combinationthereof. In a typical software implementation, the processor module mayinclude one or more microprocessor-based architectures having amicroprocessor, a random access memory (RAM), a read only memory (ROM),input/output devices and control, data and address buses connecting thesame, e.g., consistent with that shown in FIG. 6, e.g., see element 14.By way of example, the input/output devices may be configured to receivethe signaling S_(in) sensed by the sensor 100, and provide the signalingS_(in) to the signal processor 12 for further processing. By way offurther example, the input/output devices may be configured to receivethe corresponding signaling S_(out) from the signal processor 12, andprovide the corresponding signaling S_(out).

A person skilled in the art would be able to program such amicroprocessor-based architecture(s) to perform and implement suchsignal processing functionality described herein without undueexperimentation. The scope of the invention is not intended to belimited to any particular implementation using any suchmicroprocessor-based architecture or technology either now known orlater developed in the future.

The Acoustic-Based Sensor

By way of example, the present invention is disclosed based upon usingthe assignee's AIRtrac™ sensor. However, the scope of the invention isnot intended to be limited to the same. For example, embodiments areenvisioned, and the scope of the invention is intended to include, e.g.using other types or kinds of acoustic-based sensors either now known orlater developed in the future that may be configured to attach inside arotating container or drum having a known geometry, sense angularpositions of the sensor and sense associated entry and exit points whenthe sensor enters and exits concrete contained in the rotating containeror drum, and provide signaling containing information about the angularpositions and the associated entry and exit points.

The Rotating Container or Drum

By way of example, the present invention is disclosed based upon using arotating drum forming part of a concrete mixing truck. However, thescope of the invention is not intended to be limited to the same. Forexample, embodiments are envisioned, and the scope of the invention isintended to include, e.g. using other types or kinds of rotatingcontainers or drums either now known or later developed in the futurethat may be configured to receive and contain concrete, as well asrotate and mix the concrete.

The Slurry (e.g., Concrete)

By way of example, the present invention is disclosed based upon mixinga slurry like concrete using a rotating drum. However, the scope of theinvention is not intended to be limited to the same. For example,embodiments are envisioned, and the scope of the invention is intendedto include, e.g. processing other types or kinds of slurries either nowknown or later developed in the future, including other types or kindsof slurries that are sensitive to the amount of entrained air containedtherein, other types or kinds of or slurries that are mixed and pouredfrom a rotating container or drum.

Means for Attaching

Means for attaching a sensor inside a rotating container or drum isknown in the art, and the scope of the invention is not intended to belimited to any particular types or kinds thereof either now known orlater developed in the future. By way of example, the sensor may includea sensor housing that may be fastened inside the rotating container ordrum using fasteners like screws.

The Scope of the Invention

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, modifications may be made to adapt a particular situation ormaterial to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed herein as thebest mode contemplated for carrying out this invention.

What is claimed is:
 1. A system for sensing the volume, or theviscosity, or both, of concrete in a rotating container or drum,comprising: a sensor configured to attach inside a rotating container ordrum having a known geometry, sense angular positions of the sensor andsense associated entry and exit points when the sensor enters and exitsa slurry, including concrete, contained in the rotating container ordrum, and provide signaling containing information about the angularpositions and the associated entry and exit points; and a signalprocessor configured to receive the signaling, and determinecorresponding signaling containing information about a volumetricamount, or a viscosity, or both, of the slurry, including concrete, inthe rotating container or drum, based upon the signaling received.
 2. Asystem according to claim 1, wherein the sensor comprises a 3-axisaccelerometer configured to respond to the angular positions of thesensor at given times, and provide angular position signaling containinginformation about the angular positions of the sensor at the giventimes.
 3. A system according to claim 1, wherein the signal processor isconfigured to determine the volumetric amount based upon static pressurereadings contained in the signaling received that increase when thesensor enters the concrete and decrease when the sensor exits theconcrete.
 4. A system according to claim 1, wherein the sensor comprisesa pressure transducer configured to sense static pressure when thesensor enters and exits concrete contained in the rotating container ordrum and provide static pressure signaling containing information aboutthe static pressure sensed.
 5. A system according to claim 1, whereinthe signal processor is configured to determine the associated entry andexits points of the sensor using a least squares curve fittingalgorithm.
 6. A system according to claim 1, wherein the signalprocessor is configured to determine the volumetric amount based uponacoustic energy readings contained in the signaling received thatincreases when the sensor enters the concrete and decreases when thesensor exits the concrete.
 7. A system according to claim 1, wherein thesensor comprises a piston arranged in the rotating container or drum andconfigured to generate pulses; and a pressure transducer arranged in therotating container or drum at a known distance from the piston andconfigured to sense the pulses generated and provide acoustic energysignaling containing information about the pulses sensed, includingwhere the magnitude of acoustic energy sensed by the pressure transduceris low when the pulses are generated and sensed in air, and where themagnitude of acoustic energy sensed by the pressure transducer is highwhen the pulses are generated and sensed in the concrete.
 8. A systemaccording to claim 1, wherein the signal processor is configured todetermine the viscosity based upon the amount of “tilt” of the concretein the rotating container or drum and the speed of rotation of therotating container or drum.
 9. A system according to claim 8, whereinthe signal processor is configured to determine the amount of “tilt” ofthe concrete in the rotating container or drum based upon the angularpositions and the associated entry and exit points when the sensorenters and exits concrete contained in the rotating container or drum.10. A system according to claim 1, wherein the signal processor isconfigured to determine the rotation speed of the rotating container ordrum based upon the angular positions of the sensor contained in thesignaling received.
 11. A system according to claim 1, wherein thesignaling contains information about constituents of the concrete,including the amount of water, sand, rock and respective densities, andthe signal processor is configured to determine the slump of theconcrete, based upon the signaling received.
 12. A system according toclaim 1, wherein the sensor is mounted on a hatch door of the rotatingcontainer or drum.
 13. A system according to claim 1, wherein the sensoris an acoustic-based sensor.
 14. A system comprising: a signal processorconfigured to receive signaling containing information about angularpositions of a sensor attach inside a rotating container or drum havinga known geometry, as well as associated entry and exit points when thesensor enters and exits a slurry, including concrete, contained in therotating container or drum, and determine corresponding signalingcontaining information about a volumetric amount, or a viscosity, orboth, of the slurry in the rotating container or drum, based upon thesignaling received.